Currently, researches are being actively conducted in order to provide various types of multimedia services and to support a high quality and high speed data transmission in a radio communication environment. In particular, a technology associated with a multiple input multiple output (MIMO) communication system using a plurality of channels in a spatial area is in a rapid development. A single-cell MIMO communication system includes a single base station. Generally, the single-cell MIMO communication system may be classified into a single-cell multi-user MIMO communication system including a plurality of users and a single base station, and a single-cell single-user MIMO communication system including a single user and a single base station.
In the single-cell MIMO communication system, at least one base station and terminals may use a codebook. A particular space may be quantized into a plurality of vectors or matrices. The plurality of vectors or matrices may be stored as the codebook in the base station and the terminals. Each of the terminals may select any one vector or matrix from vectors or matrices included in the codebook, based on a channel between the base station and each of the terminals. The base station may also verify the selected vector matrix using the codebook. The selected vector or matrix may be used for the base station to generate a precoding vector or a precoding matrix. A scheme of performing precoding as described above is referred to as a codebook-based precoding scheme.
Also, a research regarding a multi-cell MIMO communication system including a plurality of base stations is being conducted. In the multi-cell MIMO communication system, at least two base stations may serve at least one terminal through a mutual cooperation. Since the at least two base stations cooperate with each other, it is possible to enhance a transmission rate to a terminal, particularly, a terminal that is located in a cell edge.
The codebook-based precoding scheme may be used even in the multi-cell MIMO communication system. A difference between the multi-cell MIMO communication system and the single-cell MIMO communication system lies in that the multi-cell MIMO communication system includes at least two base stations and the single-cell MIMO communication system includes a single base station. Accordingly, when the codebook-based precoding scheme used in the single-cell MIMO communication system is applied to the multi-cell MIMO communication as is, it may cause a problem.